The present invention relates to a motor vehicle headlamp of the movable reflector type, and more particularly to a motor vehicle headlamp having an improved mounting structure of an extension reflector provided between the front lens and the reflector of the headlamp.
In the case of a motor vehicle headlamp, unlike other vehicle lamps such as tail lamps and direction indicating lamps, in order to meet safety standards when assembled, adjusted or replaced, it is essential to be able to adjust the angle of inclination of the optical axis of the lamp, that is, it is necessary to adjust the angle of irradiation of the headlamp by performing a so-called aiming adjustment. For this purpose, in general, a headlamp unit including a reflector and light bulb is swingably supported within the lamp body, and the angle of inclination of the reflector is adjusted with an aiming mechanism.
In the aiming adjustment of a headlamp of the movable reflector type, in order to permit adjustment of the reflector, it is necessary to provide a space between the lamp body and the reflector and a space between the front lens and the reflector. However, these spaces can be observed through the front lens and the inner wall of the lamp body can be observed through the spaces, as a result of which the headlamp is poor in appearance. Furthermore, the spaces, which are frame-like in overall form, reduce the apparent dimensions of the inside of the headlamp.
In order to overcome these difficulties, a headlamp having an extension reflector has been proposed. The extension reflector is a cylindrical or conical member which is substantially equal in size to the front opening of the reflector and has a reflecting inner surface. The extension reflector is disposed so as to cover the above-described spaces between the reflector and the lamp body and between the reflector and the front lens.
FIG. 9 is a sectional view showing a conventional headlamp having such an extension reflector. (See European Patent No. 0 054 444). In FIG. 9, reference numeral 1 designates a vehicle body; 2, a bumper; 3, a lamp body mounted on the vehicle body 1; 4, a front lens covering the front opening of the lamp body 3; 5, a reflector arranged inside the lamp body 3 in such a manner that it can be freely inclined; 6, a light bulb; and 7, an extension reflector. The extension reflector 7 is formed integral with the lamp body 3. More specifically, the extension reflector 7 is a substantially conical member having a front opening merging with the front opening of the lamp body 3, and a rear opening substantially equal in size to the front opening of the reflector 5.
The above-described conventional headlamp is disadvantageous in that, due to the provision of the extension reflector 7, the metal mold used for forming the lamp body is necessarily bulky, and the trimming die therefor is intricate in construction. That is, the lamp body with the extension reflector is difficult to manufacture and is accordingly high in manufacturing cost.
Furthermore, there is a large gap G between the front lens 4 and the extension reflector 7. As a result, part of the output light of the light bulb 6 advances upwardly through the gap G and another part of the output light advances downwardly through the gap. These two parts of the output light, which are reflected off the bumper 2 below the gap, can dazzle the drivers of oncoming vehicles. In addition, part of the output light leaks from the side walls of the lens, making it rather difficult to provide other lamps beside the headlamp. Furthermore, the thickness t of the junction 9 of the lamp body 3 and the extension reflector 7 is large, about twice as large as the wall thickness of the lamp body 3, because the junction 9 is folded as shown in FIG. 9. Hence, when the light bulb is turned on, the junction 9 appears dark when viewed from the front. That is, the lamp is still rather poor in appearance.